3 Years in, Bitcoin Digital Money Gains Momentum : Cowrie shells, strips of leather, huge stone discs, decorated rectangles of paper. They all share something in common: at one time, people used them as currency. In 2009, when Bitcoin went live, ones and zeros were added to the list. And like each new format that preceded it, this digital currency has changed a few of money's core concepts, including who controls it and how and where it gets spent.